CdSe在高压下的电学性质及相变

Electrical Property and Phase Transition of CdSe under High Pressure

利用在金刚石压砧上集成的微电路，原位测量了CdSe多晶粉末在温度为300～450K、压力达到23 GPa时电阻率随温度和压力的变化关系。实验结果表明：在加压过程中，电阻率在2．6G Pa压力时出现的异常改变，对应着CdSe从纤锌矿向岩盐矿结构的转变，而在6．0、9．8、17．0 GPa等压力处出现的电阻率异常，则是由CdSe中的电子结构的变化所引起的；在卸压过程中，只在约14．0和3．0GPa压力下观察到了两个电阻率异常点。通过对电阻率随压力变化曲线的模拟，得出了CdSe高压相的带隙随压力的变化关系，据此预测CdSe金属化的压力应在70～100GPa之间。变温实验结果表明，在实验的温度和压力范围内，CdSe的电阻率均随温度的增加而升高。

The electrical resistivity of powdered CdSe has been measured at 300～450 K and pressure up to 23 GPa using fabricating microcircuit on a diamond anvil. It is found that during loading the pressure dependence of the electrical resistivity shows anomaly at about 2.6 GPa, corresponding to the structure transition of CdSe from wurtzite to rock-salt structure. While the anomalies observed at 6.0 GPa,9.8 GPa and 17.0 GPa are due to the electronic structure transitions. During unloading two extra anomalies can be detected which happen at 14. 0 GPa and 3.0 GPa,respectively. By fitting to the curve of pressure dependence of electrical resistivity the pressure dependence of band gap of CdSe high pressure phase has been obtained. The pressure of metallization of CdSe can be predicted to happen in the pressure range of 70～100 GPa. The elevated experiment results indicate that the electrical resistivity of CdSe increases with increasing temperature in the measured pressure and temperature range.